Clock Drawing Performance Slows for Older Adults After Total Knee Replacement Surgery

BACKGROUND: Clock drawing is a neurocognitive screening tool used in preoperative settings. This study examined hypothesized changes in clock drawing to command and copy test conditions 3 weeks and 3 months after total knee arthroplasty (TKA) with general anesthesia. METHODS: Participants included 67 surgery and 66 nonsurgery individuals >60 years who completed the digital clock drawing test before TKA (or a pseudosurgery date), and 3 weeks and 3 months postsurgery. Generalized linear mixed models assessed digital clock drawing test latency (ie, total time to completion, seconds between digit placement) and graphomotor output (ie, total number of strokes, clock size). Reliable change analyses examined the percent of participants showing change beyond differences found in nonsurgery peers. RESULTS: After adjusting for age, education, and baseline cognition, both digital clock drawing test latency measures were significantly different for surgery and nonsurgery groups, where the surgery group performed slower on both command and copy test conditions. Reliable change analyses 3 weeks after surgery found that total time to completion was slower among 25% of command and 21% of copy constructions in the surgery group. At 3 months, 18% of surgery participants were slower than nonsurgery peers. Neither graphomotor measure significantly changed over time. CONCLUSIONS: Clock drawing construction slowed for nearly one-quarter of patients after TKA surgery, whereas nonsurgery peers showed the expected practice effect, ie, speed increased from baseline to follow-up time points. Future research should investigate the neurobiological basis for these changes after TKA. Accepted for publication July 16, 2018. Funding: This work was supported by the National Institutes of Health (grant nos. R01 NR014181 to C.C.P.; R01AG055337 to C.C.P. and P.T.; UL1R001427 and P50AG047266) and the National Science Foundation (1404333 to R.D., D.L.P., and C.C.P.). Conflicts of Interest: See Disclosures at the end of the article. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (https://ift.tt/KegmMq). Clinical Trial number and registry URL: NCT01786577; clinicaltrials.gov. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute on Aging or the National Institutes of Health. Reprints will not be available from the authors. Address correspondence to Catherine C. Price, PhD, Department of Clinical and Health Psychology, University of Florida, College of PHHP, PO Box 100165, Gainesville, FL 32605. Address e-mail to cep23@phhp.ufl.edu. © 2018 International Anesthesia Research Society

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